U.S. patent application number 11/129709 was filed with the patent office on 2005-11-17 for locating, provisioning and identifying devices in a network.
This patent application is currently assigned to Cisco Technology, Inc.. Invention is credited to Droms, Ralph, Saville, Roland, Vogel, Gary Dennis JR..
Application Number | 20050253722 11/129709 |
Document ID | / |
Family ID | 38059752 |
Filed Date | 2005-11-17 |
United States Patent
Application |
20050253722 |
Kind Code |
A1 |
Droms, Ralph ; et
al. |
November 17, 2005 |
Locating, provisioning and identifying devices in a network
Abstract
Methods and devices are provided for locating, identifying and
provisioning devices in a network. According to some
implementations of the invention, a combination of EPC code
information and existing networking standards form the basis of
identifying and provisioning methods. For example, first location
information included in a DHCPDISCOVER request can be used to
determine appropriate configurations for networked devices. In some
such implementations, the first location information is read from
an RFID tag near the networked device and is inserted in the
DHCPDISCOVER request. The first location information may include
any type of absolute or relative coordinate, positioning,
cartographic or similar information and/or information from which
such information may be derived. Second location information, which
may be a logical name, is provided to the device. If the device is
an RFID reader, the second location information may be included
with reads from RFID tags that are transmitted from the RFID
reader.
Inventors: |
Droms, Ralph; (Boxborough,
MA) ; Vogel, Gary Dennis JR.; (Sunnyvale, CA)
; Saville, Roland; (Oakland Park, FL) |
Correspondence
Address: |
BEYER WEAVER & THOMAS LLP
P.O. BOX 70250
OAKLAND
CA
94612-0250
US
|
Assignee: |
Cisco Technology, Inc.
San Jose
CA
|
Family ID: |
38059752 |
Appl. No.: |
11/129709 |
Filed: |
May 12, 2005 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
60570999 |
May 13, 2004 |
|
|
|
Current U.S.
Class: |
340/572.1 ;
235/435 |
Current CPC
Class: |
H04L 29/12216 20130101;
H04L 41/0843 20130101; H04L 61/6004 20130101; H04W 8/26 20130101;
H04L 61/1511 20130101; G08B 13/2402 20130101; H04L 67/1002
20130101; H04L 29/12801 20130101; H04L 61/6063 20130101; H04W 28/08
20130101; H04L 61/2015 20130101; H04L 41/0806 20130101; H04L 41/12
20130101; H04W 4/00 20130101; H04L 67/1021 20130101; H04L 41/0883
20130101; H04L 29/12924 20130101; H04L 29/12066 20130101 |
Class at
Publication: |
340/572.1 ;
235/435 |
International
Class: |
G08B 013/14 |
Claims
We claim:
1. A method of provisioning a device, the method comprising:
initializing a radio frequency identification ("RFID") device;
reading RFID tag data from an RFID tag; inserting the RFID tag data
in an option field of a DHCPDISCOVER request; sending the
DHCPDISCOVER request to a Dynamic Host Configuration Protocol
("DHCP")server; ascertaining, based at least in part on the RFID
tag data, a location and a logical name of the RFID device;
determining, based in part on the location of the RFID device, an
appropriate configuration for the RFID device; and provisioning the
RFID device according to the appropriate configuration, wherein the
provisioning step comprises provisioning the RFID device with a
logical name.
2. The method of claim 1, wherein the RFID device is a wireless
RFID device.
3. The method of claim 2, wherein at least one step is performed by
the DHCP server.
4. The method of claim 1, wherein the ascertaining step comprises
accessing a data structure that includes RFID tag data and
corresponding location data and logical names.
5. The method of claim 1, wherein at least part of the ascertaining
step is performed by the DHCP server.
6. A method of provisioning a wireless device, the method
comprising: receiving IEEE 802.11b location data from a plurality
of wireless access points; ascertaining, based at least in part on
the IEEE 802.11b location data, a location and a logical name of a
wireless device; determining an appropriate configuration for the
wireless device according to the location; and provisioning the
wireless device, wherein the configuring step comprises supplying
the wireless device with the appropriate configuration and with a
logical name.
7. The method of claim 6, wherein the wireless device comprises one
of a manufacturing device, a radio frequency identification
("RFID") device, a portable digital assistant and a laptop
computer.
8. The method of claim 6, wherein the IEEE 802.11b location data
comprise one of time data and signal strength data.
9. A method of provisioning a device, the method comprising:
receiving a Dynamic Host Configuration Protocol ("DHCP") request;
ascertaining a location and a logical name of a device according to
information in the DHCP request; determining, based at least in
part on the location, an appropriate configuration for the device;
and providing the device with the appropriate configuration and
with a logical name.
10. The method of claim 9, wherein the ascertaining step comprises
determining a location encoded in the DHCP request.
11. The method of claim 9, wherein the ascertaining step comprises:
accessing a data structure; and mapping the information in the DHCP
request to corresponding location data.
12. A method for deploying a uniquely-provisioned radio frequency
identification ("RFID") device in a network, the method comprising:
reading first location information from a first RFID tag; forming a
DHCPDISCOVER request that includes an electronic product code
("EPC") of an RFID reader and the first location information;
sending the DHCPDISCOVER request to a Dynamic Host Configuration
Protocol ("DHCP") server; receiving provisioning information from
the DHCP server that enables a desired functionality according to
an identity and a location of the RFID reader, the provisioning
information including second location information; and provisioning
the RFID reader according to the provisioning information, thereby
enabling the RFID reader to read nearby RFID tags and to transmit
RFID tag information and second location information to an RFID
network.
13. The method of claim 12, wherein the first location information
comprises one of coordinate information and civil address
information.
14. The method of claim 12, wherein the second location information
comprises a logical name.
15. A network, comprising: a plurality of radio frequency
identification ("RFID") devices; a plurality of switches connecting
the RFID devices to the network; and a Dynamic Host Configuration
Protocol ("DHCP") server, wherein at least some of the RFID devices
comprise: means for reading first location information from a first
RFID tag; means for forming a DHCPDISCOVER request that includes an
electronic product code ("EPC") of an RFID reader and the first
location information; means for sending the DHCPDISCOVER request to
the DHCP server; means for receiving provisioning information from
the DHCP server that enables a desired functionality according to
an identity and a location of the RFID reader, the provisioning
information including second location information; and means for
provisioning the RFID reader according to the provisioning
information, thereby enabling the RFID reader to read nearby RFID
tags and to transmit RFID tag information and second location
information to an RFID network; and wherein the DHCP server
comprises: means for receiving the DHCPDISCOVER request; and means
for automatically identifying an RFID device according to a media
access control ("MAC") address and an EPC included in the
DHCPDISCOVER request and for locating the RFID device and
determining the second location information according to the first
location information included in the DHCPDISCOVER request; and
means for providing the RFID device with a desired functionality
and the second location information.
16. A method of provisioning a device, the method comprising:
initializing an RFID device; obtaining first location data;
inserting the first location data in an option field of a
DHCPDISCOVER request; and sending the DHCPDISCOVER request to a
Dynamic Host Configuration Protocol ("DHCP")server; determining
provisioning information, including a logical name, based at least
in part on the first location data; providing the provisioning
information to the device; configuring the device according to the
provisioning information; reading RFID tag data from RFID tags; and
transmitting the RFID tag data to a middleware server along with
the logical name.
17. The method of claim 16, wherein the RFID device includes global
positioning system ("GPS") capability and wherein the first
location data comprise GPS data.
18. A network for provisioning a device, the network comprising:
means for initializing a radio frequency identification ("RFID")
device; means for reading RFID tag data from an RFID tag; means for
inserting the RFID tag data in an option field of a DHCPDISCOVER
request; means for sending the DHCPDISCOVER request to a Dynamic
Host Configuration Protocol ("DHCP")server; means for ascertaining,
based at least in part on the RFID tag data, a location and a
logical name of the RFID device; means for determining, based in
part on the location of the RFID device, an appropriate
configuration for the RFID device; and means for providing the RFID
device with provisioning information comprising a logical name and
an appropriate configuration.
19. An apparatus for provisioning a wireless device, the apparatus
comprising: means for receiving IEEE 802.11b location data from a
plurality of wireless access points; means for ascertaining, based
at least in part on the IEEE 802.11b location data, a location and
a logical name of a wireless device; means for determining an
appropriate configuration for the wireless device according to the
location; and means for providing the wireless device with the
appropriate configuration and with the logical name.
20. An apparatus for provisioning a device, the apparatus
comprising: means for receiving a Dynamic Host Configuration
Protocol ("DHCP") request; means for ascertaining a location and a
logical name of a device according to information in the DHCP
request; means for determining, based at least in part on the
location, an appropriate configuration for the device; and means
for providing the device with the appropriate configuration and
with a logical name.
21. A network for deploying a uniquely-provisioned radio frequency
identification ("RFID") device in a network, the network
comprising: means for reading first location information from a
first RFID tag; means for forming a DHCPDISCOVER request that
includes an electronic product code ("EPC") of an RFID reader and
the first location information; means for sending the DHCPDISCOVER
request to a Dynamic Host Configuration Protocol ("DHCP") server;
means for receiving provisioning information from the DHCP server
that enables a desired functionality according to an identity and a
location of the RFID reader, the provisioning information including
second location information; and means for provisioning the RFID
reader according to the provisioning information, thereby enabling
the RFID reader to read nearby RFID tags and to transmit RFID tag
information and second location information to an RFID network.
22. A network for provisioning a device, the network comprising:
means for initializing an RFID device; means for obtaining first
location data; means for inserting the first location data in an
option field of a DHCPDISCOVER request; and means for sending the
DHCPDISCOVER request to a Dynamic Host Configuration Protocol
("DHCP")server; means for determining provisioning information,
including a logical name, based at least in part on the first
location data; means for providing the provisioning information to
the device; means for configuring the device according to the
provisioning information; means for reading RFID tag data from RFID
tags; and means for transmitting the RFID tag data to a middleware
server along with the logical name.
Description
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional Patent
Application No. 60/570,999 (attorney docket number CISCP378P),
entitled "Methods and Devices for Uniquely Provisioning RFID
Devices" and filed on May 13, 2004, which is hereby incorporated by
reference for all purposes. This application is related to U.S.
patent application Ser. No. 10/866,506, (attorney docket number
CISCP376), entitled "Methods and Devices for Uniquely Provisioning
RFID Devices" and filed on Jun. 9, 2004, to U.S. patent application
Ser. No. 10/866,507, (attorney docket number CISCP377), entitled
"Methods and Devices for Locating and Uniquely Provisioning RFID
Devices" and filed on Jun. 9, 2004, to U.S. patent application Ser.
No. 10/866,285, (attorney docket number CISCP378), entitled
"Methods and Devices for Assigning RFID Device Personality" and
filed on Jun. 9, 2004, to U.S. patent application Ser. No.
10/891,238 (attorney docket number CISCP379), entitled "Methods and
Devices for Determining the Status of a Device" and filed on Jul.
13, 2004, to U.S. patent application Ser. No. 10/876,410, entitled
"System and Method for Automatically Configuring Switch Ports with
Appropriate Features" and filed Jul. 21, 2004, to U.S. patent
application Ser. No. 11/010,089, (attorney docket number CISCP393),
entitled "Methods and Devices for Providing Scalable RFID Networks"
and filed on Dec. 9, 2004, to U.S. patent application Ser. No.
11/104,140, filed on Apr. 11, 2005 (attorney docket number
CISCP427), entitled "Automated Configuration of Network Device
Ports" and to U.S. patent application Ser. No. ______, filed on
Apr. 29, 2005 (attorney docket number CISCP430), entitled "Locating
and Provisioning Devices in a Network" (collectively, the
"Cross-Referenced Applications"), all of which are hereby
incorporated by reference for all purposes.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to provisioning devices in a
network.
[0004] 2. Description of the Related Art
[0005] Bar codes containing a Universal Product Code ("UPC") have
become a nearly ubiquitous feature of modern life. The vast
majority of products, as well as packages, containers and other
elements in the stream of commerce now bear a bar code to allow for
convenient tracking and inventory control.
[0006] However, bar codes have some drawbacks. Bar codes are "read
only," in that they are merely a printed set of machine-readable
parallel bars that cannot be updated. Bar codes cannot transmit
information, but instead must be read by a scanner. Bar codes must
be scanned within a relatively short distance and must be properly
oriented for the bar code to be read.
[0007] "Smart labels," generally implemented by RFID tags, have
been developed in an effort to address the shortcomings of bar
codes and add greater functionality. RFID tags have been used to
keep track of items such as airline baggage, items of clothing in a
retail environment, cows and highway tolls. As shown in FIG. 1, an
RFID tag 100 includes microprocessor 105 and antenna 110. In this
example, RFID tag 100 is powered by a magnetic field 145 generated
by an RFID reader 125. The tag's antenna 110 picks up the magnetic
signal 145. RFID tag 100 modulates the signal 145 according to
information coded in the tag and transmits the modulated signal 155
to the RFID reader 125.
[0008] Most RFID tags use one of the Electronic Product Code ("EPC"
or "ePC") formats for encoding information. EPC codes may be formed
in various lengths (common formats are 64, 96 and 128 bits) and
have various types of defined fields, which allow for
identification of, e.g., individual products as well as associated
information. These formats are defined in various documents in the
public domain. One such document is EPC Tag Data Standards Version
1.1 Rev 1.24 (EPCglobal.RTM. 2004), which is hereby incorporated by
reference for all purposes.
[0009] One exemplary RFID tag format is shown in FIG. 1. Here, EPC
120 includes header 130, EPC Manager field 140, Object class field
150 and serial number field 160. EPC Manager field 140 contains
manufacturer information. Object class field 150 includes a
product's stock-keeping unit ("SKU") number. Serial number field
160 is a 40-bit field that can uniquely identify the specific
instance of an individual product i.e., not just a make or model,
but also down to a specific "serial number" of a make and
model.
[0010] In theory, RFID tags and associated RFID devices (such as
RFID readers and printers) could form part of a network for
tracking a product (or a group of products) and its history.
However, various difficulties have prevented this theory from being
realized. One problem that has required considerable time and
energy from RF engineers is the development of lower-cost RFID tags
with acceptable performance levels. Inductively-coupled RFID tags
have acceptable performance levels. These tags include a
microprocessor, a metal coil and glass or polymer encapsulating
material. Unfortunately, the materials used in inductively-coupled
RFID tags make them too expensive for widespread use: a passive
button tag costs approximately $1 and a battery-powered read/write
tag may cost $100 or more.
[0011] Capacitively-coupled RFID tags use conductive ink instead of
the metal coil used in inductive RFID tags. The ink is printed on a
paper label by an RFID printer, creating a lower-cost, disposable
RFID tag. However, conventional capacitively-coupled RFID tags have
a very limited range. In recent years, RF engineers have been
striving to extend the range of capacitively-coupled RFID tags
beyond approximately one centimeter.
[0012] In part because of the significant efforts that have been
expended in solving the foregoing problems, prior art systems and
methods for networking RFID devices are rather primitive. RFID
devices have only recently been deployed with network interfaces.
Device provisioning for prior art RFID devices is not automatic,
but instead requires a time-consuming process for configuring each
individual device. Prior art RFID devices and systems are not
suitable for large-scale deployment of networks of RFID
devices.
[0013] Conventional RFID devices also have a small amount of
available memory. A typical RFID device may have approximately 0.5
Mb of flash memory and a total of 1 Mb of overall memory. The small
memories of RFID devices place restrictions on the range of
possible solutions to the problems noted herein. In addition, an
RFID device typically uses a proprietary operating system, e.g., of
the manufacturer of the microprocessor(s) used in the RFID
device.
[0014] Moreover, many RFID devices are deployed in a hostile
industrial environment (such as a warehouse or factory) by
relatively unskilled "IT" personnel. If a device deployed in one
location fails, for example, it may simply be removed and replaced
by a functioning device that was deployed in another location.
Therefore, it would be desirable to provide methods and devices for
uniquely and individually identifying RFID devices and their
precise location in a network.
[0015] In addition, RFID devices are being deployed with "static"
knowledge of where the device was deployed at the original time of
deployment. In practice, RFID devices are moved if another device
is damaged or not functioning. In general, it is desirable to allow
for the movement of RFID devices. However, if an RFID device is
moved, prior art systems do not know to what location the RFID
device has been moved.
[0016] It would also be desirable to provision such RFID devices
automatically for their expected use. RFID devices perform
different functions and may interface to the upstream systems
differently depending on where they are located. The functions they
perform, as well as the unique settings to perform those functions,
will be referred to herein as the device "personality." It would be
desirable not only to identify an RFID device and to determine its
location, but also to provision, configure and deploy software and
firmware to allow the RFID device to perform various functions and
roles based on location. As used herein, "provisioning" a device
can include, but is not limited to, providing network
configuration, providing personality configuration, incorporating
the device into a network database and enabling the device with
software (e.g., business process software). It would also be
desirable to provide for convenient reprovisioning and personality
updates of RFID devices.
SUMMARY OF THE INVENTION
[0017] Methods and devices are provided for locating, identifying
and provisioning devices in a network. According to some
implementations of the invention, a combination of EPC code
information and existing networking standards form the basis of
identifying and provisioning methods. For example, MAC address
information and EPC information can be combined to identify a
particular device and its location in a network. Upper-level
applications can be notified, for example, that a particular device
is available for use.
[0018] For implementations using the Dynamic Host Configuration
Protocol ("DHCP"), DHCP Options may be used to pass identification,
location and provisioning information. For example, selected DHCP
Options may be used to indicate a device type, to provide an EPC
code uniquely identifying the particular device, indicating the
company name using the device and indicating how the device is
being used.
[0019] In some implementations of the invention, location
information included in a DHCPDISCOVER request can be used to
determine appropriate configurations for networked devices. In some
such implementations, the location information is read from an RFID
tag near the networked device and is inserted in the DHCPDISCOVER
request. The location information may include any convenient type
of absolute or relative coordinate, positioning, cartographic or
similar information and/or information from which such information
may be derived. Some such implementations of the invention use
DHCPINFORM (RFC 2131) and DHCP Options (RFCs 2132 and 3004) to pass
current provisioning and personality information. Moreover, some
such implementations of the invention use the DHCPFORCERENEW
command (RFC 3203) from a DHCP server to initiate an update or to
complete reconfiguration, as required.
[0020] Some implementations of the invention provide a method of
provisioning a device. The method includes these steps:
initializing an RFID device; reading RFID tag data from an RFID
tag; inserting the RFID tag data in an option field of a
DHCPDISCOVER request; sending the DHCPDISCOVER request to a DHCP
server; ascertaining, based at least in part on the RFID tag data,
a location and a logical name of the RFID device; determining,
based in part on the location of the RFID device, an appropriate
configuration for the RFID device; and provisioning the RFID device
according to the appropriate configuration, wherein the
provisioning step comprises provisioning the RFID device with a
logical name.
[0021] The RFID device may be, for example, a wireless RFID device.
The ascertaining step may involve accessing a data structure that
includes RFID tag data and corresponding location data and logical
names. At least part of the ascertaining step may be performed by
the DHCP server.
[0022] Some aspects of the invention provide methods of
provisioning a wireless device. Some such methods include these
steps: receiving IEEE 802.11b location data from a plurality of
wireless access points; ascertaining, based at least in part on the
IEEE 802.11b location data, a location and a logical name of a
wireless device; determining an appropriate configuration for the
wireless device according to the location; and provisioning the
wireless device, wherein the configuring step comprises supplying
the wireless device with the appropriate configuration and with a
logical name.
[0023] The wireless device may be, for example, a manufacturing
device, an RFID device, a portable digital assistant or a laptop
computer. The IEEE 802.11b location data could be, for example,
time data, signal strength data or both.
[0024] Alternative methods for provisioning a device are also
provided. Some such methods include these steps: receiving a DHCP
request; ascertaining a location and a logical name of a device
according to information in the DHCP request; determining, based at
least in part on the location, an appropriate configuration for the
device; and providing the device with the appropriate configuration
and with a logical name.
[0025] The ascertaining step may involve determining a location
encoded in the DHCP request. The ascertaining step may involve
accessing a data structure and mapping the information in the DHCP
request to corresponding location data.
[0026] Another aspect of the invention provides a method for
deploying a uniquely-provisioned RFID device in a network. The
method includes these steps: reading first location information
from a first RFID tag; forming a DHCPDISCOVER request that includes
an electronic product code of an RFID reader and the first location
information; sending the DHCPDISCOVER request to a DHCP server;
receiving provisioning information from the DHCP server that
enables a desired functionality according to an identity and a
location of the RFID reader, the provisioning information including
second location information; and provisioning the RFID reader
according to the provisioning information, thereby enabling the
RFID reader to read nearby RFID tags and to transmit RFID tag
information and second location information to an RFID network.
[0027] The first location information may be, for example,
cartographic information such as coordinate information,
latitude/longitude or civil address information. The second
location information may include a logical name.
[0028] Some embodiments of the invention provide a network,
comprising: a plurality of RFID devices; a plurality of switches
connecting the RFID devices to the network; and a DHCP server. At
least some of the RFID devices include these elements: means for
reading first location information from a first RFID tag; means for
forming a DHCPDISCOVER request that includes an electronic product
code ("EPC") of an RFID reader and the first location information;
means for sending the DHCPDISCOVER request to a DHCP server; means
for receiving provisioning information from the DHCP server that
enables a desired functionality according to an identity and a
location of the RFID reader, the provisioning information including
second location information; and means for provisioning the RFID
reader according to the provisioning information, thereby enabling
the RFID reader to read nearby RFID tags and to transmit RFID tag
information and second location information to an RFID network.
[0029] The DHCP server includes these elements: means for receiving
the DHCPDISCOVER request; means for automatically identifying an
RFID device according to a media access control address and an EPC
included in the DHCPDISCOVER request; means for locating the RFID
device and determining the second location information according to
the first location information included in the DHCPDISCOVER
request; and means for providing the RFID device with a desired
functionality and the second location information.
[0030] Some aspects of the invention provide yet another method of
provisioning a device. The method includes these steps:
initializing an RFID device; obtaining first location data;
inserting the first location data in an option field of a
DHCPDISCOVER request; sending the DHCPDISCOVER request to a Dynamic
Host Configuration Protocol ("DHCP")server; determining
provisioning information, including a logical name, based at least
in part on the first location data; providing the provisioning
information to the device; configuring the device according to the
provisioning information; reading RFID tag data from RFID tags; and
transmitting the RFID tag data to a middleware server along with
the logical name. In some implementations, the RFID device includes
global positioning system ("GPS") capability and the first location
data comprise GPS data. The methods of the present invention may be
implemented, at least in part, by hardware and/or software. For
example, some embodiments of the invention provide computer
programs embodied in machine-readable media. The computer programs
include instructions for controlling one or more devices to perform
the methods described herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] FIG. 1 is a diagram illustrating an RFID tag.
[0032] FIG. 2 illustrates an exemplary RFID network according to
the present invention.
[0033] FIG. 3 is a block diagram of an exemplary RFID reader that
may be configured to perform some methods of the present
invention.
[0034] FIG. 4 is a block diagram of an exemplary RFID printer that
may be configured to perform some methods of the present
invention.
[0035] FIG. 5 is a block diagram of an exemplary RFID system that
may be configured to perform some methods of the present
invention.
[0036] FIG. 6 is a flow chart that provides an overview of some
methods of the present invention.
[0037] FIG. 7 is a flow chart that provides an overview of
alternative methods of the present invention.
[0038] FIG. 8 is a flow chart that provides an overview of some
implementations of the present invention.
[0039] FIG. 9A is a network diagram that illustrates an alternative
embodiment of the invention.
[0040] FIG. 9B illustrates a Global Location Number ("GLN").
[0041] FIG. 9C illustrates one exemplary location reference field
of the GLN illustrated in FIG. 9B.
[0042] FIG. 10 is a flow chart that outlines an alternative method
of the invention.
[0043] FIG. 11 is a network diagram that illustrates another
embodiment of the invention.
[0044] FIG. 12 is a flow chart that outlines yet another method of
the invention.
[0045] FIG. 13 illustrates one exemplary format of an RFID read
that includes a logical device name and device location data.
[0046] FIG. 14 is a flow chart that outlines another aspect of the
present invention.
[0047] FIG. 15 illustrates an example of a network device that may
be configured to implement some methods of the present
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0048] In this application, numerous specific details are set forth
in order to provide a thorough understanding of the present
invention. It will be obvious, however, to one skilled in the art,
that the present invention may be practiced without some or all of
these specific details. In other instances, well known process
steps have not been described in detail in order not to obscure the
present invention.
[0049] Although the present invention involves methods and devices
for locating, identifying and provisioning individual RFID devices
in a network, many aspects of the present invention can be applied
to identifying and provisioning other types of devices in a
network. For example, the present invention may also be used for
locating, identifying and provisioning manufacturing devices,
networked sensor devices, IPphones, portable digital assistants and
other networked devices, including wireless and wired devices.
Similarly, although much of the discussion herein applies to
implementations using the DHCP protocol, the present invention is
not protocol-specific and may be used, for example, in
implementations using UPnP, 802.1ab or similar discovery protocols.
Likewise, while the implementations described herein refer to
exemplary DHCP Options, other DHCP Options may advantageously be
used to implement the present invention.
[0050] The methods and devices of the present invention have very
broad utility, both in the public and private sectors. Any
enterprise needs to keep track of how its equipment is being
deployed, whether that equipment is used for commercial purposes,
for military purposes, etc. RFID devices that are networked
according to the present invention can provide necessary
information for allowing enterprises to track equipment and
products (or groups of products). The information that will be
provided by RFID devices that are networked according to the
present invention will be of great benefit for enterprise resource
planning, including the planning of manufacturing, distribution,
sales and marketing.
[0051] Using the devices and methods of the present invention, RFID
tags and associated RFID devices (such as RFID readers and
printers) can form part of a network for tracking a product and its
history. For example, instead of waiting in a checkout line to
purchase selected products, a shopper who wishes to purchase
products bearing RFID tags can, for example, transport the products
through a door that has an RFID reader nearby. The EPC information
regarding the products can be provided to an RFID network by the
reader and can be used to automatically update a store inventory,
cause a financial account to be debited, update manufacturers',
distributors' and retailers' product sales databases, etc.
[0052] Read/write RFID tags can capture information regarding the
history of products or groups of products, e.g., temperature and
other environmental changes, stresses, accelerations and/or
vibrations that have acted upon the product. It will be
particularly useful to record such information for products that
relatively more subject to spoilage or other damage, such as
perishable foods and fragile items. By using the methods of the
present invention, this information will be used to update
databases maintained by various entities (e.g., manufacturers,
wholesalers, retailers, transportation companies and financial
institutions). The information will be used not only to resolve
disputes (for example, regarding responsibility for product damage)
but also to increase customer satisfaction, to avoid health risks,
etc.
[0053] Some aspects of the invention use a combination of EPC code
information and modified versions of existing networking standards
for identifying, locating and provisioning RFID devices, such as
RFID readers and RFID printers, that are located in a network. An
example of such a network is depicted in FIG. 2. Here, RFID network
200 includes warehouse 201, factory 205, retail outlet 210,
financial institution 215 and headquarters 220. As will be
appreciated by those of skill in the art, network 200 could include
many other elements and/or multiple instances of the elements shown
in FIG. 2. For example, network 200 could include a plurality of
warehouses, factories, etc.
[0054] In this illustration, products 227 are being delivered to
warehouse 201 by truck 275. Products 227, which already include
RFID tags, are delivered through door 223. In this example, RFID
reader 252 is connected to port 262 of switch 260. Here, switches
230 and 260 are connected to the rest of RFID network 200 via
gateway 250 and network 225. Network 225 could be any convenient
network, but in this example network 225 is the Internet. RFID
reader 252 reads each product that passes through door 223 and
transmits the EPC code corresponding to each product on RFID
network 200.
[0055] RFID tags may be used for different levels of a product
distribution system. For example, there may be an RFID tag for a
pallet of cases, an RFID tag for each case in the pallet and an
RFID tag for each product. Accordingly, after products 227 enter
warehouse 201, they are assembled into cases 246. RFID printer 256
makes an RFID tag for each of cases 246. In this example, RFID
printer 256 is connected to port 266 of switch 260. RFID printer
256 could operate under the control of PC 247 in warehouse 201, one
of PCs 267 in headquarters 220, or some other device.
[0056] RFID reader 224, which is connected to port 214, reads the
EPC code of each case 246 and product 227 on conveyor belt 244 and
transmits this information on network 200. Similarly, RFID reader
226, which is connected to port 216, reads the EPC code of each
case 246 and product 227 that exits door 204 and transmits this
information on network 200. Cases 246 are loaded onto truck 285 for
distribution to another part of the product chain, e.g., to retail
outlet 210.
[0057] Each of the RFID devices in network 200 preferably has a
"personality" suitable for its intended use. For example, device
252 could cause reassuring tone to sound and/or a green light to
flash if an authorized person or object enters door 223. However,
device 252 might cause an alarm to sound and/or an alert to be sent
to an administrator on network 200 if a product exits door 223 or
an unauthorized person enters or exits door 223.
[0058] FIG. 3 illustrates an RFID reader that can be configured to
perform methods of the present invention. RFID reader 300 includes
one or more RF radios 305 for transmitting RF waves to, and
receiving modulated RF waves from, RFID tags. RF radios 305 provide
raw RF data that is converted by an analog-to-digital converter
(not shown) and conveyed to other elements of RFID reader 300. In
some embodiments, these data are stored, at least temporarily, by
CPU 310 in memory 315 before being transmitted to other parts of
RFID network 200 via network interface 325. Network interface 325
may be any convenient type of interface, such as an Ethernet
interface.
[0059] Flash memory 320 is used to store a program (a "bootloader")
for booting/initializing RFID reader 300. The bootloader, which is
usually stored in a separate, partitioned area of flash memory 320,
also allows RFID reader 300 to recover from a power loss, etc. In
some embodiments of the invention, flash memory 320 includes
instructions for controlling CPU 310 to form "DHCPDISCOVER"
requests, as described below with reference to FIG. 6, to initiate
a provisioning/configuration cycle. In some implementations, flash
memory 320 is used to store personality information and other
configuration information obtained from, e.g., a DHCP server during
such a cycle.
[0060] However, in preferred implementations, such information is
only stored in volatile memory 315 after being received from, e.g.
a DHCP server. There are advantages to keeping RFID devices "dumb."
For example, a network of dumb RFID devices allows much of the
processing load to be centralized (e.g., performed by server 270 of
network 200), instead of being performed by the RFID devices.
Alternatively, the processing load can be decentralized, but only
to trusted devices (such as PC 247 of network 200).
[0061] Configuration information is downloaded from, e.g., a
central server to memory 315. Updates may be instigated by the
central server or selected, trusted devices. New versions of the
image file (e.g., the running, base image necessary to operate the
RFID device) are copied into flash memory 320. Alternative
embodiments of RFID devices implement the methods of the present
invention yet lack flash memory.
[0062] Newer RFID devices also include dry contact input/output
leads to connect to signal lights, industrial networks or the
equivalent. These newer RFID devices typically have evolved in the
amount of memory, flash, CPU capacity and methods of determination
of the number, type and content of RFID tags in their field of
view.
[0063] FIG. 4 is a block diagram illustrating an exemplary RFID
printer 400 that may be configured to perform some methods of the
present invention. RFID printer 400 has many of the same components
as RFID reader 300 and can be configured in the same general manner
as RFID reader 300.
[0064] RFID printer also includes printer interface 430, which may
be a standard printer interface. Printer interface prints a label
for each RFID tag, e.g. according to instructions received from
network 200 via network interface 425.
[0065] RF Radio 405 is an outbound radio that is used to send RF
signals to the antenna of an RFID tag under the control of CPU 410,
thereby encoding information (e.g. an EPC) on the tag's
microprocessor. Preferably, RF Radio 405 then checks the encoded
information for accuracy. The RFID tag is sandwiched within the
label produced by printer interface 430.
[0066] FIG. 5 illustrates RFID system 500 that includes control
portion 501 and RF radio portion 502. The components of control
portion 501 are substantially similar to those described above with
reference to FIGS. 3 and 4. Interconnect 530 of control portion 501
is configured for communication with interconnect 535 of RF radio
portion 502. The communication may be via any convenient medium and
format, such as wireless, serial, point-to-point serial, etc.
Although only one RF radio portion 502 is depicted in FIG. 5, each
control portion 501 may control a plurality of RF radio portions
502. RFID system 500 may be deployed on a single framework or
chassis (e.g., on a forklift) or in multiple chassis.
[0067] The DHCP protocol is used in some preferred implementations
of the present invention because it offers various convenient
features. For example, the DHCP protocol allows pools or "scopes"
of TCP/IP addresses to be defined. A DHCP server can temporarily
allocate or "lease" these TCP/IP addresses to host devices. An IP
address that is not used for the duration of the lease is returned
to the pool of unallocated IP addresses. In addition, the DHCP
server will provide all related configuration settings, such as the
default router, Domain Name Service ("DNS") servers, subnet mask,
etc., that are required for the proper functioning of TCP/IP.
[0068] For implementations using the DHCP protocol, DHCP Options
may be used to pass provisioning information. The DHCP protocol is
defined in RFC 2131 and DHCP Options are set forth in, for example,
RFCs 2132, 3004 and 3046. RFCs 2131, 2132, 3004 and 3046 are hereby
incorporated by reference for all purposes.
[0069] In some preferred implementations, an EPC corresponding to
an RFID device is put inside a DHCP request sent from the RFID
device to a DHCP server. The EPC uniquely identifies the RFID
device. Some implementations employ Domain Name Service ("DNS") and
dynamic DNS ("DDNS") to allow yet easier identification of RFID
devices.
[0070] An overview of some such implementations of the present
invention will now be described with reference to FIG. 6. It will
be appreciated by those of skill in the art that the steps
illustrated and described herein are not necessarily performed in
the order indicated. Moreover, it will be appreciated that some
aspects of the invention may be performed using more (or fewer)
steps than are indicated herein. A device that sends out an
initiation for an IP address to a DHCP server does so by way of a
packet that includes a "DHCPDISCOVER" request. This command
includes the media access control ("MAC") address of the device.
According to some preferred implementations, the RFID device (e.g.,
CPU 310 of RFID Reader 300) forms a "DHCPDISCOVER" request packet
that includes information in various DHCP Option fields (step 601).
The RFID device encodes DHCP "vendor class identifier" Option 60
with a code indicating that the device is an RFID device. In other
words, "RFID" will be a new type of "vendor class," encoded in
Option 60.
[0071] In this example, the RFID device encodes its own EPC in the
field reserved for Option 43 (vendor specific information, defined
in RFC 2132), Option 61 or Option 125 (vendor-identifying vendor
specific information, defined in RFC 3925). The RFID device also
encodes a company name, e.g., of the company that supplies, owns or
is using the RFID device, in DHCP Option 43.
[0072] Option 77 (user class option, defined in RFC 3004) or Option
124 (vendor-identifying class option, defined in RFC 3925) may be
used in various ways according to different implementations of the
invention. In some implementations, Option 77 or Option 124 will be
used to indicate the type of RFID device, e.g., that the RFID
device is an RFID reader or an RFID printer. In some
implementations, Option 77 or Option 124 can also include
information regarding the functionality or "personality" of the
RFID device. For example, Option 77 or Option 124 could indicate
that the RFID device is an inbound RFID reader, an outbound RFID
reader, an RFID reader or printer on an assembly line, a retail
store, etc.
[0073] Referring once again to FIG. 2, if the request is from RFID
device 252, that device would encode information in Option 77 or
Option 124 indicating that the device is an RFID reader. In some
implementations, Option 77 or Option 124 also indicates that RFID
device 252 has a personality suitable for being positioned at an
entrance door. Some implementations include more detailed
information about the current personality of device 252. For
example, Option 77 or Option 124 may indicate that in addition to
reading EPC codes and uploading them to the RFID network, device
252 will also cause a green light to flash if an authorized person
or object enters door 223 and will cause a red light to flash, an
alarm to sound and an alert to be sent to an administrator on the
network if a product exits door 223. This information could be
encoded, for example, according to a number that corresponds to one
of a range of suitable personalities for an RFID reader at an
entrance door.
[0074] It is desirable to determine and provide location
information for RFID devices in a network. Switches and wireless
bridges with Ethernet or switch ports are considered static and
have assigned names and locations. According to some
implementations of the invention, location information is added,
for example to an RFID device's DHCPDISCOVER request, by the
network device to which the RFID device is attached (step 610).
[0075] Some such implementations use DHCP Option 82 (RFC 3046) in a
new way to determine the switch port and switch to which an RFID
device is connected. For example, a switch may insert the following
two information elements into any DHCP request from an attached
RFID device: Option 82, Sub-Option 1: Agent Circuit ID and Option
82, Sub-Optionb 2: Agent Remote ID. The Agent Circuit ID is the
name or identifier of the switch. The Agent Remote ID is the name
or identifier of the switch port.
[0076] For example, if the request is from RFID device 226 of FIG.
2, network device 230 adds location information to the request in
step 610. Here, the location information would be encoded in Option
82 and would include information identifying network device 230 and
port 216, to which RFID reader 226 is attached.
[0077] In alternative embodiments wherein the RFID device is
capable of determining its own location (e.g., from GPS
coordinates), the RFID device may encode location information in
the DHCPDISCOVER request or in other commands.
[0078] There can be multiple DHCP servers serving the same network.
How the servers respond can depend, for example, on whether each
server is busy, whether it has served out all its addresses, etc.
As RFID pilot networks emerge and develop, they will be interleaved
with existing networks, including networks that employ the DHCP
protocol. DHCP servers that are provisioning RFID devices (e.g.
server 270 of FIG. 2) will respond to "DHCPDISCOVER" commands
identifying a class of the device as "RFID," e.g., encoded in
Option 60. Those of skill in the art will appreciate that other
Options may be used for this purpose. Conversely, DHCP servers that
are not provisioning RFID devices will not respond to
"DHCPDISCOVER" commands identifying a class of the device as
"RFID." Further, if a non-RFID DHCP server does respond, the RFID
device will be able to determine from the DHCP options response
that it has received an incomplete DHCP response and will discard
it and will prefer responses from RFID DHCP servers. Accordingly,
the methods of the present invention allow for the integration of
RFID networks within the existing framework of the DHCP
protocol.
[0079] In step 615, the DHCP server determines whether there is
information regarding the requesting device within a database of
information regarding known RFID devices, their intended functions,
configurations, etc. For example, the DHCP server may inspect the
EPC encoded in a request and determine whether there is information
for a device with a corresponding EPC in the database.
[0080] If so, in step 620, the server compares information in the
DHCP request with stored information regarding the RFID device.
This information may be in a database (e.g., stored in one of
storage devices 265) that is updated, for example, by IT personnel
responsible for the RFID network. For example, MAC address
information and EPC information can be combined to identify a
particular device and its location in a network. Upper-level
applications can be notified, for example, that a particular RFID
device is available for use.
[0081] By inspecting the received data, the server can then
determine the type, identity, location and personality (if any) of
the RFID device. By comparing the received data with information in
the database, the server can then determine, for example, if that
precise RFID device has moved and where it is now located. In
preferred implementations, the DHCP server may determine the
current personality of the RFID device (e.g., by inspecting the
Option 77 data) and may compare the current personality with a
desired personality.
[0082] In step 625, the DHCP server provides the RFID device with
configuration information, etc., indicated in the database. For
example, the DHCP server may indicate the RFID device's time
server, SYSLOG server, the location of the device's configuration
files, image files, etc. If the RFID device's current personality
does not match the desired personality (or if the request does not
indicate a current personality), according to some implementations
the DHCP server can provide the device with information (e.g., a
computer program, configuration settings, etc.) for enabling the
desired personality.
[0083] For example, suppose that the EPC code indicates that the
device is RFID reader 252 and Option 77 indicates that RFID device
252 has a personality suitable for being positioned at an entrance
door. However, the location information in the request may indicate
that the requesting device has been moved and is now located at an
exit door. Alternatively, the database may indicate that the device
is positioned at a door that has been used as an entrance door, but
which now will be used as an exit door. This may be a periodic
(e.g. hourly, daily, weekly, or monthly) change at a manufacturing
facility or warehouse, or may be due to a reconfiguration of the
facility.
[0084] Therefore, the desired personality for RFID device 252 is
now a personality appropriate for an exit door. However, there may
be a range of different "exit door" personalities that could be
provided to device 252 depending, for example, on the capabilities
of the device making the request, the expected uses of the exit
door, etc. For example, a device with fewer capabilities (e.g., a
smaller memory) may be enabled for relatively simpler exit door
functionality. For example, such a device may be enabled to, e.g.,
make a green light flash when particular type of product is exiting
the door and to transmit a notification message to IT personnel
and/or cause an alarm to sound if other items are exiting the
door.
[0085] However, a device with greater capabilities may be enabled
for relatively more complex exit door functionality. For example,
the device could be enabled to cause a green light to flash if a
particular type of product is exiting at an expected time, if the
number of products exiting the door is within a predetermined
range, etc.
[0086] This flexibility in reassigning device personality allows an
RFID network to cause the same device type to have multiple
personalities based upon location, time of day, or any other
suitable criteria. Moreover, this flexibility allows for movement
or relocation of devices (whether or not this movement has been
approved in advance) and then having devices automatically
"repersonalized," as appropriate for the new location. In addition,
it allows for specialized functionality on a per device, per locale
basis.
[0087] However, in some circumstances there may be no information
in the database regarding the device. For example, the device may
be a new RFID device that has just been activated in the RFID
network for the first time (step 630). In this example, the device
is placed in a "walled garden" for devices that are not trusted
devices. Step 630 may involve assigning the device a non-routable
IP address for a predetermined length of time via a DHCPOFFER
command. According to some implementations, the DHCP server
performs step 630 when there is information in the database
regarding the device that is inconsistent with information in the
request.
[0088] Preferably, step 630 includes notifying an upper-layer
application that the device has made the request. In this way, IT
personnel responsible for the site within which the RFID device is
located will be notified that the RFID device exists and has made a
request.
[0089] According to some implementations, step 630 involves setting
the DHCP Ti timer for a short time interval, for example, 60
seconds. In this example, the RFID device will continue to send
DHCP requests to the server every 60 seconds and the server will
send "ACKs" to the device until one of two events occurs: (1) the
server has been updated (e.g., by IT personnel responsible for the
site within which the RFID device is located); or (2) the
connection between the server and the RFID device goes down. (Step
635.)
[0090] If the server is updated within the predetermined time, this
indicates that an IT person has determined that the RFID device
making the request is a trusted device. Accordingly, the method
proceeds to step 625. If not, the device remains classified as an
untrusted device (step 630). Preferably, the device's status may
still be changed to that of a trusted (and therefore provisioned)
device, e.g., according to subsequent input from IT personnel.
[0091] After an initial provisioning configuration cycle (e.g., as
described above), RFID devices may need to be reprovisioned or have
their personalities changed. As noted above, it is desirable for an
RFID device to take on unique provisioning and personalities
depending on the desired functionality of the RFID device at a
particular time. The desired functionality may be determined
according to the location and capabilities of the RFID device. Some
devices may be provided with the same personality for a relatively
longer time, e.g., months or years. However, it may be desirable to
change the personality and/or provisioning information of an RFID
device in a relatively shorter time, e.g., prior to the time that a
DHCP T1 timer expires. The majority of currently-deployed RFID end
devices do not support RFC 3203 (DHCP Reconfigure Extension).
[0092] The present invention encompasses a variety of methods for
accomplishing these goals. One such method will now be described
with reference to FIG. 7. Method 700 begins with a determination of
whether to send information to a network device regarding the
current personality of the RFID device (step 701). Here, the RFID
device will send the information to a DHCP server if a
predetermined period of time has elapsed. In this example, the
predetermined period of time is one hour, but it could be any
convenient period of time.
[0093] If it is time for another DHCPREQUEST or DHCPINFORM message
to be sent to the DHCP server, the RFID device forms the request
(step 705). If not, the current personality is maintained (step
702). In this example, the information will be sent in a DHCP
request (RFC 2131) combined with DHCP Option 125, Option 61 or
Option 43 set to the RFID device's EPC (or equivalent) and Option
77 set to the RFID device's current personality. Using DHCPREQUEST,
DHCPINFORM and DHCP Options, the RFID device is able to pass
current identification, provisioning and personality
information.
[0094] In this example, a cached secret (e.g., hashed with the
contents of the DHCP message including the client EPC) will be
included with the DHCP request in order to secure the response. The
secret could be provided, for example, during an earlier
provisioning stage, e.g., the initial provisioning stage of the
RFID device. The secret could be used in the DHCPINFORM validation
process and for other processes.
[0095] The request is sent in step 710. Preferably, a relay agent
updates the request with location information, as described above
(step 715).
[0096] In step 720, the server compares the information in the
request with stored information (e.g., in a lookup table or a
database) to determine whether an update or a complete
reconfiguration of the RFID device is required. If not, the process
returns to step 701. If so, the server provides the RFID device
with the necessary update and/or reconfiguration information (step
725).
[0097] The RFID device triggers the update and/or reconfiguration
determination in the foregoing example. However, in other
implementations, another device (e.g., the DHCP server) and/or a
person initiates this determination. For example, the DHCP server
could initiate a periodic process of comparing a desired RFID
device personality with the last known RFID device personality.
Alternatively, an IT worker could send information (e.g., to the
DHCP server, to the RFID device or to another device) indicating a
desired change in personality.
[0098] According to some implementations of the invention, a DHCP
server causes an update or a complete reconfiguration using a
DHCPFORCERENEW command as defined by RFC 3203, which is hereby
incorporated by reference in its entirety. The CPU of the RFID
device registers the DHCPFORCERENEW command and starts a new
provisioning cycle, for example as described above with reference
to FIG. 6.
[0099] In order to secure the command, in this example a cached
secret is hashed within the command. For example, the secret can be
included with the EPC code of the RFID device.
[0100] One method for creating an authentication key is as
follows:
[0101] MD-5 (EPC, Challenge, Secret)
[0102] By adding in the variable of a random Challenge, no replay
attacks of the hash code could be used. Because the EPC is
included, the authentication can be further validated to come from
a specific device.
[0103] The foregoing methods allow for unique determination and
provisioning of RFID devices by time of day, not simply by device
"type," "class" or "location." Moreover, the foregoing methods
allow for ongoing verification/auditing of what the end device
roles are. In addition, these methods allow operation managers to
have enterprise resource planning systems control end devices to
allow for increased functionality.
[0104] FIG. 8 is a flow chart that illustrates an exemplary
business application of the present invention. Those of skill in
the art will appreciate that the example described below with
reference to FIG. 8 is but one of many applications of the
invention.
[0105] In step 805, an RFID device has already been provisioned
according to one of the previously-described methods. The condition
of the RFID device is comparable to that of a device at step 640 in
method 600, shown in FIG. 6 and described above. In this example,
the RFID device is an RFID reader that is positioned near an exit
door of a retail store. Therefore, in the previous steps, the
device has been provisioned with a personality that is appropriate
for its role.
[0106] In step 810, a shopper exits the door with a number of
selected products. In step 815, the RFID reader reads the RFID tags
of each product and extracts the EPC codes and related product
information (e.g., the price of each product).
[0107] The RFID reader also reads an RFID tag that identifies the
shopper and the shopper's preferred account(s) that should be
debited in order to purchase the products. For example, the shopper
may have an RFID tag embedded in a card, a key chain, or any other
convenient place in which this information is encoded. The accounts
may be various types of accounts maintained by one or more
financial institutions. For example, the accounts may be one or
more of a checking account, savings account, a line of credit, a
credit card account, etc. Biometric data (e.g., voice, fingerprint,
retinal scan, etc.) from the shopper may also be obtained and
compared with stored biometric data in order to verify the
shopper's identity.
[0108] In step 820, the RFID reader transmits the product
information, including the EPC codes, on the RFID network. In this
example, the information is first sent to a financial institution
indicated by the shopper's RFID tag.
[0109] In step 825, the financial institution that maintains the
shopper's selected account determines whether there are sufficient
funds (or whether there is sufficient credit) for the shopper to
purchase the selected products. If so, the shopper's account is
debited and the transaction is consummated (step 830).
[0110] In this example, the shopper has the option of designating
one or more alternative accounts. Accordingly, if the first account
has insufficient funds or credit, it is determined (e.g., by a
server on the RFID network) whether there the shopper has indicated
any alternative accounts for making purchases (step 835). If so,
the next account is evaluated in step 825. If it is determined in
step 835 that there are no additional accounts designated by the
shopper, in this example some form of human intervention takes
place. For example, a cashier of the retail store could assist the
shopper in making the purchases in a conventional manner.
[0111] If some or all of the products are purchased, information
regarding the purchased products (including the EPC codes) are
transmitted on the RFID network. For example, this information is
preferably forwarded to one or more devices on the RFID network
that are configured to update one or more databases maintained by
the retail store or the manufacturers/producers, distributors,
wholesalers, etc., of the purchased products (step 840). In some
implementations, information regarding the shopper is also
transmitted on the RFID network (e.g., if the shopper has
authorized such information to be released). This product
information (and optionally shopper information) may be used for a
variety of purposes, e.g., in the formation of various types of
business plans (e.g., inventory re-stocking, marketing, sales,
distribution and manufacturing/production plans).
[0112] Some implementations of the invention provide alternative
methods of provisioning devices, including but not limited to RFID
devices. Some such methods will now be discussed with reference to
FIGS. 9 et seq.
[0113] In FIG. 9A, RFID reader 905 is in communication with switch
910. This communication may be via a wired link, as illustrated by
optional link 915 between RFID reader 905 and port 917.
Alternatively, the communication may be via a wireless link, e.g.,
via wireless link 920 between antenna 925 of RFID reader 905 and
antenna 927 of access point 930. RFID device 907 is connected via
line 918 to port 919.
[0114] Switch 910, as well as switches 912, 914 and 916, can
communicate with DHCP server 935 via network 940. Network 940 may
be any convenient type of network, but in this illustration at
least part of network 940 includes a portion of the Internet.
[0115] In some implementations of the invention, DHCP server 935
performs tasks that, in other implementations, are performed by
device 945. Device 945 may be one of various types of computing
devices, including a host device, a server, etc. In some
implementations, device 945 is a Lightweight Directory Access
Protocol ("LDAP") server. LDAP is a set of protocols for accessing
information directories and is based on the standards contained
within the X.500 standard, but is significantly simpler. Unlike
X.500, LDAP supports TCP/IP. In some implementations, DHCP server
935 and device 945 are in the same chassis 950. In other
implementations, DHCP server 935 and device 945 are in direct
communication (as shown by link 955) or communicate via network
940.
[0116] Accordingly, RFID reader 905 can read RFID tags (including
but not limited to location tag 960) and transmit them to devices
in communication with network 940. Preferably, location tag 960 is
positioned in a relatively fixed location, e.g., is mounted on a
wall, a door frame, or another structural element of a building. In
alternative embodiments, location tag 960 is portable.
[0117] Location tag 960 includes what will sometimes be referred to
herein as "location data," "location information" or the like. The
location information may include any convenient type of absolute or
relative coordinate, positioning, cartographic or similar
information and/or information from which such information may be
derived. For example, in some implementations location tag 960
includes latitude/longitude, X,Y coordinate information and/or
elevation information. In other implementations, location tag 960
includes "civil address" information, which may include street
address, building, floor, room/area and/or other such
information.
[0118] Alternatively, the location information may be in the form
of a code, such as a numerical or alphanumeric code, from which
absolute location information (such as coordinate,
latitude/longitude, civil address, etc.) may be derived. For
example, a data structure accessible by DHCP server and/or device
945 may include codes and corresponding absolute location
information. Accordingly, DHCP server and/or device 945 may access
the data structure and determine absolute location information that
corresponds to a code encoded in location tag 960. The data
structure may be a look-up table, a database, etc. The data
structure may be stored in a local memory or in one or more of
networked storage devices 947.
[0119] Middleware servers 952 and 954 provide data collection and
filtering services, such as taking out redundancies, searching for
particular RFID tag reads, etc. Accordingly, only a portion of the
data received by the middleware servers is routinely made available
to higher-level applications. Middleware servers are sometimes
referred to herein as "ALE" (application level event) devices or
the like.
[0120] IT personnel monitoring the system, troubleshooting, etc.,
may use a device such as management station 957, which is a desktop
computer in this example. A management station may be configured to
receive, display and analyze raw and/or filtered reads and to
perform follow-up tasks such as interrogating devices in the
network.
[0121] Location tag 960 may be encoded in any convenient manner,
including by proprietary methods and/or methods that conform, at
least in part, to existing standards. In general, it is preferable
to deploy location tags that are encoded according to existing
standards in order to simplify programming of related devices, to
avoid non-uniqueness problems and generally to lower the costs of
implementing the present invention. Location tag 960 may be formed,
e.g., as an RFID tag or as any type of bar code. One example of a
format for at least a portion of location tag 960 is shown in FIG.
9B. Here, location tag 960 is in the general format of a Global
Location Number ("GLN"). Some exemplary GLN formats are defined,
for example, in the "Global Location Number (GLN) Implementation
Guide," (Uniform Code Council, 2002), which is hereby incorporated
by reference for all purposes. Accordingly, location tag 960
includes a 13-digit GLN. Field 965 is a company prefix field, which
indicates the prefix assigned to an entity by the Uniform Code
Council or an EAN member organization. Field 972 is a check digit
field that contains a one-digit number used to ensure data
integrity.
[0122] The length of location reference field 970, which is a
nine-digit field in this example, varies according to the length of
the assigned company prefix field 965. Location reference field 970
may be assigned to identify uniquely a selected location.
Accordingly, location reference field 970 may be customized
according to an organization's desires and/or requirements. In the
example shown in FIG. 9C, location reference field 970 has been
defined by an entity to according to a 3-digit building field 975,
a 2-digit floor field 980, a 1-digit function field 985 and a
3-digit area field 990. In this example, the location is a
particular door in a receiving area of a warehouse.
[0123] FIG. 10 is a flow chart that outlines method 1000 according
to the invention. In step 1001, a device initializes. According to
method 1000, the device obtains location data before the device is
configured with an IP address and other network configuration
information. (Step 1005.)
[0124] In some implementations of the invention, the location data
are obtained in step 1005 by reading a location tag that is
positioned nearby. Accordingly, location tags have previously been
positioned in locations where devices were expected to be used. The
identifiers and locations of the location tags have preferably been
recorded in a central management system. In some such
implementations, when a device (e.g., a wireless RFID reader) is
first turned on, the device prompts the user to "swipe" the reader
past a location tag. Swiping may not be necessary if, for example,
the location tag is an RFID tag and the reader is capable of
reading tags at a sufficient distance.
[0125] In alternative implementations, the location data are
obtained in step 1005 according to other methods, e.g., from an
associated device that has Global Positioning System ("GPS")
capability. In some such implementations, the device itself
includes GPS functionality.
[0126] In step 1008, the location data are included in an option
field of the DHCPDISCOVER request, for example in option 43 (RFC
2132) or option 125 (RFC 3925). These RFCs are hereby incorporated
by reference for all purposes. The DHCPDISCOVER request is then
sent to a DHCP server. (Step 1010.) In step 1015, it is determined
whether the device's location can be determined from the location
data in the DHCPDISCOVER request. The determining step includes
extracting the location data from an option field of the
DHCPDISCOVER request. As noted above, in some implementations the
location data may be a code that can be used to cross-reference
objective location data that could be meaningful for the purpose of
device provisioning. In other implementations (e.g., as described
above with reference to FIGS. 9B and 9C), such objective location
data are encoded in the request itself.
[0127] The process of determining and/or evaluating the location
data may be performed by the DHCP server itself (e.g., by DHCP
server 935 of FIG. 9A) or may be performed, at least in part, by
another device (e.g., by device 945 of FIG. 9A). Information
relevant to steps 1015, 1018 and 1020 maybe stored by one of these
devices, by a local storage device or by networked storage devices
947. (See FIG. 9A.) If objective location data can be determined in
step 1015, the process continues to step 1018. If not, the process
ends.
[0128] In this example, objective location data were encoded as
shown in FIG. 9C and it is determined in step 1015 that the device
is located near the indicated receiving door of a particular floor
of a warehouse. In step 1018, it is determined whether there are
stored configuration data that correspond to the objective location
data determined in step 1015. Either step 1015 or step 1018 (in
this example, step 1018) also involves determining a device type,
e.g., according to methods discussed elsewhere herein. Here, it is
determined in step 1018 that the device is a particular type of
RFID reader. Moreover, it is determined in step 1018 that
configuration data appropriate for that type of RFID device and for
the location determined in step 1015 have previously been stored.
In this example, it is determined in step 1018 that location data
for the device, such as a logical name, are also available.
[0129] Accordingly, in step 1020 an appropriate IP address, other
network configuration information, location data and an operating
system image for the RFID reader are obtained. Such data will
sometimes be collectively referred to herein as "configuration
data" or the like. In this example, an appropriate device
personality has also been stored. This personality is determined in
step 1018 and is provided in step 1025 through a DHCP message
exchange, using one or more DHCP Options. For example, coordinate
based location information can be returned in the "DHCP Option for
Coordinate-based Location Configuration Information" (RFC 3825),
which is hereby incorporated by reference. Civic address location
information can be returned in the "DHCP Option for Civic Addresses
Configuration Information" (draft-ietf-geopriv-dhcp-civil-04),
which is also incorporated by reference. Other location tags can be
returned as a "Vendor-Identifying Vendor Option" (RFC 3925), which
has already been incorporated by reference herein. A logical name
could be returned via DHCP Option 12.
[0130] DHCP and DNS can accomplish provisioning based on location.
The DHCP server could return a "random" address from a pool of
addresses and also could return a specific host name to the RFID
reader. Middleware typically has a pre-configured specific IP
address or specific host name, corresponding to a particular RFID
reader. It will be apparent to those of skill in the art that
hard-coding a specific IP address in the middleware will not work
if the DHCP server is handing out "random" IP addresses from a
pool.
[0131] Therefore, in some implementations of the invention, the
specific host name is hard-coded within the middleware server. When
the DHCP server hands back a "random" IP address corresponding to a
particular RFID reader, it can update a dynamic DNS server. The DNS
server binds the "random" IP address to the specific host name. In
this case, because the DHCP server assigned the host name to the
device based upon the location of the device (e.g., from the DHCP
Option 82 information) one can ensure that the IP address is bound
to the correct host name.
[0132] The device is configured accordingly, e.g., as described
elsewhere herein. (Step 1030.) In some preferred implementations, a
middleware server will instruct the reader to include location
information within each tag read, in whatever form the middleware
server designates, e.g., as a location EPC, as geographic
coordinates or as a logical name of the reader (i.e. device name or
host name). For example, the middleware server could send XML
commands instructing the reader to set its name to a logical name
(e.g., "dock door 100"). In some such implementations, the logical
name will include additional civic address information (e.g.,
"warehouse A") and/or cartographic information, such as (x,y,z)
coordinates, latitude/longitude, etc.
[0133] Location data received in the provisioning process are
preferably stored locally, e.g., in a memory of each provisioned
RFID reader. When the middleware initiates a session to the reader,
it queries the DNS server using the hard-coded host name. The DNS
server responds with the IP address bound to that host name and the
middleware is able to connect to the RFID reader.
[0134] After RFID readers are provisioned and configured according
to methods of the present invention, the RFID readers read RFID
tags (step 1035) and transmit RFID data from the RFID tags
(sometimes referred to herein as "raw reads" or the like) to
middleware servers, such as middleware servers 952 and 954 of FIG.
9A. In some preferred implementations of the invention, an RFID
reader will also encode and transmit location data (such as a
logical name) obtained during the provisioning process, along with
the raw reads. (Step 1040.) An example of such a read is described
below with reference to FIG. 13.
[0135] In some such implementations, these location data are
transmitted with every raw read. As noted elsewhere herein, a
logical name has meaning without the need to cross reference, e.g.,
a device ID number. Accordingly, a logical name would have meaning
to IT personnel monitoring the system, troubleshooting, or
otherwise trying to determine the significance of the reads. Such
tasks may be performed, for example, via management station
957.
[0136] Some implementations of the invention use alternative
methods of determining a device's location. For example, some
methods that are suitable for wireless devices use location
determination techniques that are outlined in one or more of the
IEEE 802.11 specifications, (e.g., 802.11b), which are hereby
incorporated by reference for all purposes.
[0137] Some such implementations will now be described with
reference to the network diagram of FIG. 11 and the flow chart of
FIG. 12. FIG. 11 depicts wireless device 1105, which is a wireless
RFID reader in this example. In alternative implementations,
wireless device 1105 may be another type of wireless device, such
as a portable digital assistant or a laptop computer having a
wireless interface. The signals from wireless device 1105 can be
detected by wireless access points ("WAPs") 1101, 1102 and 1103,
which are in communication with switches 1111 and 1112.
[0138] According to method 1200 of FIG. 12, wireless device 1105
initializes and forms an association with access point 1101 (step
1205). All 802.11 devices associate with only a single access point
at any one time. Therefore, wireless device 1105 can only associate
with a single access point. Access points 1102 and 1103 can "see"
wireless device 1105 because a wireless network is a shared medium.
However, wireless device 1105 directs its traffic towards access
point 1101, with which it has an association.
[0139] According to the 802.11b specification, a wireless device
will periodically send out a special wireless frame (packet) which
is specifically understood to go to all access points. The special
frame, which is typically implementation dependent, usually
contains an identifier for the particular wireless device. Such
special frames will be referred to herein as "location frames" or
the like. Accordingly, in step 1210 wireless device 1105 sends out
a location frame that is received by access points 1101, 1102 and
1103. The location frame includes an identifier, which could be the
MAC address of wireless device 1105, some other identification
number, an EPC value coded into the RFID device, etc.
[0140] When an access point receives a location frame, the access
point forwards the location frame to a management server that
aggregates the information from various access points. Each access
point may insert a timestamp of when it received the frame and/or
the power level (Received Signal Strength Indicator or "RSSI") of
the received frame before forwarding it to the management server.
These data will sometimes be referred to herein as "IEEE 802.11b
location data" or the like.
[0141] Such IEEE 802.11b location data may include what could be
termed "triangulation data," in that the data may be used to locate
the wireless device by triangulation techniques. However, some
types of IEEE 802.11b location data are not, strictly speaking,
triangulation data. Instead, these data reference other location
information, e.g., system map data.
[0142] Accordingly, in step 1215, access points 1101, 1102 and 1103
insert IEEE 802.11b location data into the location frames received
from wireless device 1105 and forward the location frames to
management server 1120. Therefore, management server 1120 will
receive multiple frames containing the device identifier for
wireless device 1105 from different access points. Switch 1113 is
shown in FIG. 11 to be hard wired to management server 1120, DHCP
server 1125, LDAP server 1130 and switch 1111. Switch 1113 is
depicted as being in communication with switch 1112 via network
1160, which is a local area network in this example. However, it
will be appreciated by those of skill in the art that this is
merely a simple example of how these and other devices of network
1100 may communicate. For example, switch 1113 may communicate with
one or more of management server 1120, DHCP server 1125, LDAP
server 1130, switch 1112 and switch 1111 via a network such as an
intranet and/or the Internet.
[0143] In step 1225, management server 1120 attempts to determine
the location of wireless device 1105 using the IEEE 802.11b
location data in the location frames. The access points have
preferably been mapped into the management server, so their
location is known. Based upon the IEEE 802.11b location data (e.g.,
the RSSI or timestamp) in the special frames, the management server
can use algorithms to determine the location of wireless device
1105.
[0144] Management server 1120 may show the location of wireless
device 1105 on a map that was pre-configured in a management
station at the same time the access points were added to the
management station. This location could be indicated in terms of a
geographical coordinate. Alternatively, or additionally, management
server may be configured to designate portions of a map to
correspond to a predetermined location name such as "dock door 101"
or "back stockroom."
[0145] If management server 1120 cannot determine the location of
wireless device 1105, method 1200 ends. The location may
nonetheless be determined by alternative methods described herein.
However, if management server 1120 can determine the location of
wireless device 1105, management server 1120 will store the
location and may update a memory of another device, e.g., of LDAP
server 1130. (Optional step 1230.)
[0146] In step 1235, wireless device 1105 sends a DHCPDISCOVER
request, with a device identifier, to DHCP server 1125. Unlike the
special location frame, the DHCPDISCOVER request only goes to the
access point with which wireless device 1105 has an association
(access point 1101). Switch 1111, to which access point 1101 is
connected, may optionally add location data as described elsewhere
herein. For example, switch 1111 may include location data in
Option 82. Switch 1111 forwards the DHCPDISCOVER request to DHCP
server 1125 via switch 1113. In some implementations, switch 1113
functions as a relay agent and inserts a gateway address in the
DHCPDISCOVER request if DHCP server is on a separate IP subnet.
[0147] In step 1250, DHCP server 1125 queries management server
1120 and/or LDAP server 1130 to determine whether there is a
location corresponding to information (e.g., ID information) in the
DHCPDISCOVER request. If not, method 1200 ends.
[0148] In one such example, DHCP server 1125 queries management
server 1120 for the location of the device upon receiving the
DHCPDISCOVER request. DHCP server 1125 could use the MAC address,
EPC value or another identifier coded into the DHCPDISCOVER request
in order to reference wireless device 1105 to management server
1120. Management server 1120 could return the location of the RFID
device to the DHCP server via the network. Depending on the
implementation, management server 1120 could return a geographical
coordinate or a predetermined location name such as "dock door
101."
[0149] DHCP server 1125 could query LDAP server 1130 for such
information in a similar fashion. If management server 1120 is
updating LDAP server 1130, DHCP server 1125 could obtain these and
other data from LDAP server 1130.
[0150] If a device location is determined, DHCP server 1125
determines whether there are configuration data, personality data,
etc. appropriate for the location and for the device type indicated
in the DHCPDISCOVER request as described elsewhere herein. If there
are not, method 1200 ends. If such data are found, DHCP server 1125
obtains these data (step 1255) and provides them to wireless device
1105. (Step 1260.) In this example, it is determined in step 1250
that location data for the device, such as a logical name, are also
available. Accordingly, these data are also obtained in step 1255
and provided to wireless device 1105 in step 1260. Wireless device
1105 is provisioned accordingly in step 1265.
[0151] After an RFID reader is provisioned and configured, the RFID
reader is ready for normal operation. The RFID reader will read
RFID tags (step 1270) and transmit raw reads from the RFID tags to
middleware servers, such as middleware servers 952 and 954 of FIG.
9A or middleware server 1170 of FIG. 11. In this example, the RFID
reader will also encode and transmit location data (such as a
logical name) obtained during the provisioning process, along with
the raw reads. (Step 1275.) The logical name would have meaning to
IT personnel monitoring the system, troubleshooting, etc.
[0152] FIG. 13 illustrates one exemplary format of an RFID read
that includes a logical device name and/or device location data. In
this example, the RFID reader is communicating with a middleware
server over an Ethernet and has encoded RFID tag read 1300 in an
XML document. Accordingly, the outermost layer of encapsulation is
Ethernet layer 1305. Within Ethernet layer 1305 are IP datagram
1310 and TCP layer 1315. Accordingly, XML document 1325 is embedded
in HTTP message 1320, which is encapsulated in a TCP/IP packet
within an Ethernet frame.
[0153] In this example, XML document 1325 includes both a logical
name ("dockDoor100") and latitude/longitude/altitude data, as
follows:
1 <?xml version="1.0" encoding="UTF-8"> . . .
<rfidReader> <readerName name="dockDoor100">
<readerLocation> <locationCoordinates>
<lattitude>053C1F751</lattit- ude>
<longitude>F50BA5B97</longitude>
<altitude>00006700</altitude> </locationCoordinate-
s> </readerLocation> <readPoint id="1"> <epc
>000000000000000000000001</epc> </readPoint>
</readerName> </rfidReader>
[0154] Within the XML document, there is a single EPC tag read
value ("<epc>00000000000000000000000</epc>").
[0155] FIG. 14 is a flow chart that outlines a simplified method
1400 for using the location data and RFID tag reads provided by
some aspects of the invention. Some steps of method 1400 may be
performed, for example, by (and/or via) a management station such
as management station 957 of FIG. 9A or management station 1150 of
FIG. 11.
[0156] In step 1405, location data and RFID tag reads are received.
In some systems of the prior art, a raw read might identify the
originating RFID reader by using an identification number, such as
a MAC address of the reader. The raw reads from a number of RFID
readers are displayed, e.g., on a display monitor of a management
station.
[0157] Instead of identifying a raw read as being from an RFID
reader identified by a number, according to some aspects of the
invention the read is associated with a location and/or a function
via a logical name such as "dock door A," "Building 22, 3.sup.rd
floor, conference room B," etc. Accordingly, it may be easier for
IT personnel to determine when a problem is indicated (step 1415)
and/or to more quickly address the problem (step 1420) and resolve
it (step 1425) when such a problem is indicated.
[0158] In one example, an IT person is managing an RFID network for
a factory and associated warehouses. The IT person is using a
management station for this purpose, which has a screen that
displays information about the various components of the network.
For example, the screen may normally display many rows of entries
that indicate at least part of a raw read and corresponding
location data. In this example, the management station includes
software that allows the IT person to display RFID reads according
to various criteria, at least some of which correspond to location
data. For example, the IT person is able to display all reads
within a certain time frame that came from a particular location,
e.g., from a particular dock door of a particular building.
Accordingly, the IT person will be able to detect problems more
easily. (Step 1415.)
[0159] The management station may also include software that
provides for automatic notification when a predetermined event
happens (or fails to happen). For example, a box may pop up on the
display screen that indicates a problem, e.g., "I have not heard
from [logical name of device] in 2 hours" or "[logical name of
device] just sent a message indicating antenna failure." (Step
1415.)
[0160] The IT person may address such a problem (step 1420) more
readily, because the problem indicated will be associated with a
particular location name/logical name. For example, the problem may
be addressed by interrogating an RFID device and/or the associated
middleware server, by rebooting an RFID device, by notifying a
person who works in or near the location indicated to replace a
defective RFID device, etc. After the problem is resolved (step
1425), the management station will continue to receive and monitor
RFID reads.
[0161] FIG. 15 illustrates an example of a network device that may
be configured to implement some methods of the present invention.
Network device 1560 includes a master central processing unit (CPU)
1562, interfaces 1568, and a bus 1567 (e.g., a PCI bus). Generally,
interfaces 1568 include ports 1569 appropriate for communication
with the appropriate media. In some embodiments, one or more of
interfaces 1568 includes at least one independent processor 1574
and, in some instances, volatile RAM. Independent processors 1574
may be, for example ASICs or any other appropriate processors.
According to some such embodiments, these independent processors
1574 perform at least some of the functions of the logic described
herein. In some embodiments, one or more of interfaces 1568 control
such communications-intensive tasks as media control and
management. By providing separate processors for the
communications-intensive tasks, interfaces 1568 allow the master
microprocessor 1562 efficiently to perform other functions such as
routing computations, network diagnostics, security functions,
etc.
[0162] The interfaces 1568 are typically provided as interface
cards (sometimes referred to as "line cards"). Generally,
interfaces 1568 control the sending and receiving of data packets
over the network and sometimes support other peripherals used with
the network device 1560. Among the interfaces that may be provided
are Fibre Channel ("FC") interfaces, Ethernet interfaces, frame
relay interfaces, cable interfaces, DSL interfaces, token ring
interfaces, and the like. In addition, various very high-speed
interfaces may be provided, such as fast Ethernet interfaces,
Gigabit Ethernet interfaces, ATM interfaces, HSSI interfaces, POS
interfaces, FDDI interfaces, ASI interfaces, DHEI interfaces and
the like.
[0163] When acting under the control of appropriate software or
firmware, in some implementations of the invention CPU 1562 may be
responsible for implementing specific functions associated with the
functions of a desired network device. According to some
embodiments, CPU 1562 accomplishes all these functions under the
control of software including an operating system (e.g. Linux,
VxWorks, etc.), and any appropriate applications software.
[0164] CPU 1562 may include one or more processors 1563 such as a
processor from the Motorola family of microprocessors or the MIPS
family of microprocessors. In an alternative embodiment, processor
1563 is specially designed hardware for controlling the operations
of network device 1560. In a specific embodiment, a memory 1561
(such as non-volatile RAM and/or ROM) also forms part of CPU 1562.
However, there are many different ways in which memory could be
coupled to the system. Memory block 1561 may be used for a variety
of purposes such as, for example, caching and/or storing data,
programming instructions, etc.
[0165] Regardless of network device's configuration, it may employ
one or more memories or memory modules (such as, for example,
memory block 1565) configured to store data, program instructions
for the general-purpose network operations and/or other information
relating to the functionality of the techniques described herein.
The program instructions may control the operation of an operating
system and/or one or more applications, for example.
[0166] Because such information and program instructions may be
employed to implement the systems/methods described herein, the
present invention relates to machine-readable media that include
program instructions, state information, etc. for performing
various operations described herein. Examples of machine-readable
media include, but are not limited to, magnetic media such as hard
disks, floppy disks, and magnetic tape; optical media such as
CD-ROM disks; magneto-optical media; and hardware devices that are
specially configured to store and perform program instructions,
such as read-only memory devices (ROM) and random access memory
(RAM). The invention may also be embodied in a carrier wave
traveling over an appropriate medium such as airwaves, optical
lines, electric lines, etc. Examples of program instructions
include both machine code, such as produced by a compiler, and
files containing higher level code that may be executed by the
computer using an interpreter.
[0167] Although the system shown in FIG. 15 illustrates one
specific network device of the present invention, it is by no means
the only network device architecture on which the present invention
can be implemented. For example, an architecture having a single
processor that handles communications as well as routing
computations, etc. is often used. Further, other types of
interfaces and media could also be used with the network device.
The communication path between interfaces/line cards may be bus
based (as shown in FIG. 15) or switch fabric based (such as a
cross-bar).
Other Embodiments
[0168] Although illustrative embodiments and applications of this
invention are shown and described herein, many variations and
modifications are possible which remain within the concept, scope,
and spirit of the invention, and these variations would become
clear to those of ordinary skill in the art after perusal of this
application.
[0169] Accordingly, the present embodiments are to be considered as
illustrative and not restrictive, and the invention is not to be
limited to the details given herein, but may be modified within the
scope and equivalents of the appended claims.
* * * * *